Communication apparatus and helmet

ABSTRACT

A communication apparatus includes a support structure ( 41 ) that is fastenable to a safety helmet ( 58 ). A vibration conduction microphone ( 54 ) is carried by the support structure. The vibration conduction microphone and the speaker enclosure ( 43 ) are positioned so that, when the support structure is fastened to the safety helmet, the vibration conduction microphone and the speaker enclosure come into contact with a rear of the wearer&#39;s head.

FIELD OF THE INVENTION

The present invention is concerned with improved means for facilitatingcommunication by workers in noisy and hazardous environments.

BACKGROUND TO THE INVENTION

A problem that is particularly faced by workers, such as fire-fighters,in noisy and often hazardous environments, is that it is difficult toclearly communicate with fellow workers, and other parties, when wearingapparatus such as helmets and breathing masks. Several approaches tothis problem are described in the prior art. For example, in JapanesePatent Application publication No. JP 11215581-A to Temco Japan Co. Ltd,there is described a bone conduction head-set suitable for mountingunder a helmet. The bone conduction microphone is mounted on the top ofthe head. Such an apparatus is believed to be potentially dangerous asin the event of a load falling upon a wearer of the apparatus the boneconduction microphone may depress the wearer's skull. Other approachesto facilitating communication have involved the use of headphones whichcover the ears. While such an approach allows the wearer to readily hearsound from the headphones it prevents the wearer from hearing ambientnoise and engaging in direct communication with those nearby.

Where personnel operate in high ambient noise environments there may bea need for hearing protection to be used. However, the use of hearingprotection typically interferes with the provision of clearcommunication.

A further problem that is faced in providing a communication means forfirefighters is that the communication means may be damaged by waterused by the firefighters in the course of their work.

It is an objective of the present invention to provide means foraddressing the above described problems.

SUMMARY OF THE INVENTION

According to a first aspect of the present invention there is provided acommunication apparatus including:

a support structure that is fastenable to a safety helmet;

a vibration conduction microphone that is carried by the supportstructure; and

a speaker enclosure that is also carried by the support structure, thevibration conduction microphone and the speaker enclosure beingpositioned so that, when the support structure is fastened to the safetyhelmet, the vibration conduction microphone and the speaker enclosurecome into contact with a rear of a wearer's head, in use.

The support structure may be configured to be fastened to a nape strapof the safety helmet.

Preferably both the vibration conduction microphone and the speakerenclosure are waterproof.

According to a second aspect of the invention there is provided a helmetthat includes:

a vibration conduction microphone that is positioned on a part of thehelmet; and

a speaker enclosure that is also positioned on a part of the helmet, thevibration conduction microphone and the speaker enclosure beingpositioned so that when the helmet is worn, the vibration conductionmicrophone and the speaker enclosure come into contact with a rear ofthe wearer's head.

According to a third aspect of the present invention there is provided aspeaker enclosure including:

a housing disposed about a speaker, the housing having at least oneopening;

a resilient diaphragm attached to the housing for contact with the headof a person in use; and

a membrane sealing the at least one opening thereby shielding thespeaker from water.

In a preferred embodiment the housing has first and second openings. Theresilient diaphragm may seal the first opening for contact with the headof a person in use and the second opening is sealed by the waterproofmembrane.

Preferably the second opening is protected by an acousticallytransparent cover.

In a preferred embodiment a cone of the speaker faces the membrane andthe acoustically transparent cover.

It is desirable that the housing be dimensioned so that in use energytransfer from the speaker to the person via the resilient diaphragm ismaximised.

An electrical cable is typically coupled to the speaker.

Preferably the housing includes an aperture and the electrical cablepasses through the aperture.

It is desirable that the aperture be filled with a sealant.

Preferably the sealant provides strain relief to the electrical cable.

Preferably the housing includes a mounting means that may be configuredto receive a strap, belt or the like.

A transducer may be located inside the housing adjacent to the resilientdiaphragm in order that the speaker enclosure be used to pick-upvibrations from a wearer as well as to transfer vibrations to thewearer. Preferably the transducer is an accelerometer.

The accelerometer is preferably acoustically insulated, for example bymeans of a visco-elastic layer. A spacer may be attached between thevisco-elastic layer and the speaker.

According to a fourth aspect of the invention there is provided avibration conduction microphone including:

a transducer;

an acoustic isolator disposed about the accelerometer; and

a housing.

Preferably the acoustic isolator includes a visco-elastic materialPreferably the acoustic isolator further includes a holder for holdingthe visco-elastic material.

In a preferred embodiment the transducer comprises an accelerometer.

In one embodiment the housing is a flexible body of, for example,urethane, configured to receive the accelerometer, acoustic isolator andholder.

The housing may include a mounting means. The mounting means may beconfigured to receive a strap, belt or the like.

According to another aspect of the present invention there is provided ahelmet mountable communications apparatus, including transducing meansconsisting of a vibration conduction microphone and/or a speakerenclosure;

wherein, the transducing means is mounted at the rear of the helmet sothat in use the transducing means contacts the rear of a wearer's head.

Preferably the helmet mounting includes both the vibration conductionmicrophone and the speaker conduction.

Preferably the vibration conduction microphone is of the type previouslydescribed. Similarly it is preferable that the speaker enclosure is ofthe type previously described.

The transducing means may be conveniently mounted to, or suspended from,a head support member of the helmet such as an internal headband or napestrap of the helmet.

The helmet mounting may be provided in combination with a helmet oralternatively it may be provided separately for retro-fitting to ahelmet.

According to another aspect of the invention there is provided acommunication apparatus comprising: a vibration conduction microphone; aspeaker enclosure including a speaker and arranged to couple vibrationsfrom the speaker to bone of a wearer; and attachment means coupled toeach of said microphone and said speaker enclosure to facilitateattachment to an item of headgear for placement of said microphone andspeaker enclosure against a rearward portion of the wearer's head, inuse.

In some exemplary embodiments, the speaker enclosure includes: a firstregion to couple vibrations from the speaker to bones of the wearer'shead; and a second region to couple vibrations from said speaker elementto air for conventional hearing by the wearer. In some exemplaryembodiments, the speaker enclosure includes: a housing about a speaker;and a resilient diaphragm attached to the housing, said diaphragmcomprising the first region to couple vibrations from the speaker tobones of the wearer's head; the housing defining at least one openingcomprising the second region to couple vibrations from said speaker toair for conventional hearing by the wearer. In some exemplaryembodiments, a membrane is arranged on the housing to seal the at leastone opening thereby shielding the speaker from water. In some exemplaryembodiments, there is provided an acoustically transparent cover for thefirst opening. In some exemplary embodiments, an electrical cable isconnected to the speaker to transmit electrical signals to the speaker,the housing defining an aperture accommodating the electrical cable anda sealant interposed between the cable and the housing, the sealantbeing selected to provide strain relief to the electrical cable. In someexemplary embodiments, a transducer is arranged in the housing adjacentthe resilient diaphragm so that the speaker enclosure can be used topick up vibrations from the wearer as well as to transfer vibrations tothe wearer.

In some exemplary embodiments, the attachment means comprises: a firstheadgear strap engagement means fast with the vibration conductionmicrophone to receive a strap of the headgear; and a second headgearstrap engagement means fast with the vibration conduction speakerenclosure to receive said, or an additional, strap of the headgear. Insome exemplary embodiments, the first and second headgear strapengagement means include recesses formed into respective bodies of thevibration conduction microphone and the vibration conduction speakerenclosure to receive the headgear straps.

In some exemplary embodiments, the attachment means comprises a supportstructure to which the vibration conduction microphone and the vibrationconduction speaker enclosure are mounted. In some exemplary embodiments,the headgear comprises a helmet and wherein the attachment means isadapted to be mounted to an internal support of the helmet. In someexemplary embodiments, the headgear comprises a helmet and wherein theattachment means is adapted to be connected to a nape adjustment strapof the helmet.

In some exemplary embodiments, the microphone includes: a housing; atransducer that is positioned in the housing; and an acoustic isolatorthat is also positioned in the housing and disposed about thetransducer. In some exemplary embodiments, the acoustic isolatorincludes a visco-elastic material. In some exemplary embodiments, theacoustic isolator further includes a holder for holding thevisco-elastic material. In some exemplary embodiments, the transducercomprises an accelerometer. In some exemplary embodiments, the housingcomprises a flexible body configured to receive the accelerometer,acoustic isolator and holder.

Further preferred features of the invention will be apparent from thefollowing detailed description which will be made with reference to anumber of drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

In order that this invention may be more readily understood and put intopractical effect, reference will now be made to the accompanyingdrawings which illustrate typical preferred embodiments of theinvention:

FIG. 1 is a first perspective view of a speaker enclosure according toan embodiment of an aspect of the invention.

FIG. 2 is a second perspective view of the speaker enclosure of FIG. 1.

FIG. 3 is a plan view of the speaker enclosure of FIGS. 1 and 2

FIG. 3A is a cross-sectional view of the speaker enclosure of FIGS. 1and 2.

FIG. 4 is a perspective view of a speaker enclosure according to afurther embodiment of the invention.

FIG. 5 is a plan view of the speaker enclosure of FIG. 4

FIG. 5A is a cross sectional view of the speaker enclosure of FIGS. 4and 5.

FIG. 6 is a first perspective view of a vibration conduction microphoneaccording

to an embodiment of another aspect of the present invention.

FIG. 7 is a second perspective view of the vibration conductionmicrophone of FIG. 6.

FIG. 8 is a plan view of the vibration conduction microphone of FIGS. 6and 7.

FIG. 8A is a cross-sectional view of the vibration conduction microphoneof FIGS. 6 and 7.

FIG. 9 depicts a use of the speaker enclosure of FIG. 1 and thevibration conduction microphone of FIG. 6.

FIG. 10 is a first perspective view of a helmet mounting according to afurther aspect of the invention.

FIG. 11 is a second perspective view of the helmet mounting of FIG. 10

FIG. 12 is a plan view of the helmet mounting of FIGS. 10 and 11

FIGS. 12A and 12B are cross sectional views.

FIG. 13 is an external view of a typical helmet

FIG. 14 is a view of the interior of said typical helmet showing theposition of the helmet mounting of FIG. 10 in use.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

FIG. 1 is a perspective view of a first side of a speaker enclosure 50according to a preferred embodiment of the present invention. The term“speaker enclosure” is used herein to refer to a loaded speakerenclosure, i.e., one including a speaker. The speaker enclosure includesa housing 2 which incorporates a mounting means in the form of slots 3arranged for securing speaker enclosure 50 to a belt, strap or the like.A cover in the form of a grill 4 covers one end of housing 2. Grill 4 isacoustically transparent due to a number of perforations 5 to allow theescape of sound from a speaker located in the housing 2. A cable 6protrudes through a port 7 formed in housing 2. Cable 6 is connected toa speaker located in the housing 2 as will be shortly explained.

FIG. 2 is a further perspective view of the speaker enclosure 50 showinga diaphragm 8 which is incorporated into housing 2 opposite grill 4.FIG. 3A is a cross section through the speaker enclosure showing aninternally located speaker 9 with cone 10 facing grill 4 as shown.Between the speaker cone and the grill there is located a waterproofmembrane 11. Port 7 is sealed with a waterproof sealant 12 whichsurrounds cable 6 and provides strain relief to the cable. It will berealised that the inside of speaker enclosure 50 is waterproofed byvirtue of membrane 11, diaphragm 8 and sealant 12.

In use, speaker enclosure 50 is mounted to the side of the head, bymeans of a band or strap through slots 3, so that diaphragm 8 is broughtinto contact with the side of the head but preferably not over the ear.An electrical signal from some communication source, for example awalkie-talkie radio, is applied by means of cable 6 to speaker 9. Inresponse speaker cone 10 vibrates so that sound may be heard emanatingfrom grill 4. Simultaneously diaphragm 8 vibrates against the side ofthe head thereby causing the auricles of the ear to vibratesympathetically and allowing the hearer to perceive communication. Thedepth of housing 2, indicated by dimension D in FIG. 3A, is tuned tomaximise the coupling of energy from speaker 9 into the wearer's headvia diaphragm 8.

FIG. 4 is a perspective view of a speaker enclosure 52 according to afurther embodiment of the invention. With reference to FIGS. 1 to 3A,like reference numerals refer to like parts, unless otherwise specified.

FIG. 5A is a cross section of speaker enclosure 52. An acoustic isolator13, which preferably includes a visco-elastic material such asSorbothane®, surrounds a transducer in the form of accelerometer 14. Apreferred accelerometer is the Knowles Corporation's 1771 single axisaccelerometer. Acoustic isolator 13 further includes a transducer cup 15which anchors the visco-elastic material and which is secured to therear of speaker 16. Cabling 17 from accelerometer 14 runs out throughport 18 along with cabling 17 from speaker 16. A resilient diaphragm 19forms part of housing 2 as previously described.

In use, resilient diaphragm 19, is placed against the head of a person.In order to transmit a voice signal to the person, speaker 16 isappropriately energised. Vibrations from the speaker are transmitted viaresilient diaphragm 19 into the head of the person where they causesympathetic vibration of the auricles thereby causing the person toperceive the voice signal via bone-based sound conduction. Sound wavesgenerated by speaker 16 also emanate out through membrane 20 and grill21 and are heard by the person in the normal way. Conversely when theperson speaks vibrations pass through resilient diaphragm 19, are pickedup by accelerometer 14 and transduced into an electrical signal that isconveyed by cable 17 for further processing. Accelerometer 14 isprevented from picking-up spurious external sounds by acoustic isolator13.

FIG. 6 is a perspective view of a vibration conduction microphone 54according to a preferred embodiment of a further aspect of the presentinvention. FIG. 7 is a second perspective view of vibration conductionmicrophone 54, FIG. 8A is a cross sectional view of the vibrationconduction microphone 54.

Housing 22 has slots 23 for receiving a strap or belt for mountingmicrophone 54 to the head of a wearer and incorporates a diaphragm 24.Preferably housing 22 is a flexible body of, for example, urethane.Housing 22 has a recess 26.

An acoustic isolator 25 which includes a visco-elastic material such asSorbothane, surrounds a transducer in the form of an accelerometer 27. Apreferred accelerometer is the Knowles Corporation's 1771 single axisaccelerometer. Acoustic isolator 25 is a transducer holder in the formof cup 28 which is secured into recess 26 by means of waterproof sealant(not shown). A cable 29 protrudes through a port 30 formed in housing22. Cable 29 is connected to accelerometer 27 for conveying electricalsignals generated by the accelerometer during use for processing. Aflexible waterproof sealant 31 seals port 30. It will be realised thatthe inside of housing 22 is waterproofed by virtue of diaphragm 24 andsealant 31.

In use vibration conduction microphone 54 is secured to the head of awearer by threading a belt or strap through slots 23 and securing itwith diaphragm 24 against the wearer's head. As the wearer speaks,vibrations corresponding to the speech are produced and these areconveyed to the accelerometer 27 which converts them into electricalsignals that are conveyed by cable 29 for processing by suitableelectronic circuitry.

FIG. 9 shows a person 32 wearing a typical breathing apparatus mask 33that includes a number of head support straps 34 and 35. Attached tostrap 34 is a vibration conduction microphone 36, of the type describedwith reference to FIG. 6. Attached to strap 35 is a speaker enclosure ofthe type described with reference to FIG. 1. Cabling 37 from microphone36 and the speaker enclosure 38 is connected to suitable electroniccommunication modules (not shown).

The communication modules may include signal conditioning circuitry suchas filters to improve the clarity of the communications. It will benoted that the wearer's ear 39 is not covered by speaker enclosure 38 sothat the wearer may readily hear ambient sound or wear hearingprotection in areas of high ambient noise.

FIG. 10 is a first perspective view of a communication apparatus 56according to an embodiment of a further aspect of the present invention.

FIG. 11 is a second perspective view of communication apparatus 56. FIG.12A is a cross-sectional view of a speaker enclosure 43 of the apparatus56. Enclosure 43 is similar to enclosure 50. FIG. 12B is across-sectional view of a vibration conduction microphone 42 of theapparatus 56. Vibration conduction microphone 42 is similar to themicrophone 54. It follows that, with reference to FIGS. 1 to 9, likereference numerals refer to like parts, unless otherwise specified.

Communication apparatus 56 includes a support structure 41 (shown as ahelmet mount in FIG. 14). As can be seen in FIGS. 10 to 12, the speakerenclosure 43 and the microphone 42 are positioned in the supportstructure 41.

FIG. 13 is an external view of a typical helmet 58 as used, for example,by fire fighters. FIG. 14 is a view of the interior of said typicalhelmet 58 showing the positioning of the helmet mountable communicationapparatus of FIG. 10.

Communication apparatus 56 is suspended from a nape adjustment strap 40of helmet 58. Support structure 41 is configured to be connected to napeadjustment strap 40. Speaker enclosure 43 and microphone 42 arepositioned on support structure 41 so that diaphragm 24 of vibrationconduction microphone 42 and diaphragm 8 of speaker enclosure 43 makecontact with the rear of the wearer's head.

The inventors have discovered that the vibration conduction microphoneand/or the speaker enclosure may be located at the rear of the head. Asdiscussed previously, this location is in contrast to prior artapproaches which mount bone conduction transducers at the top of thehead which is a potentially dangerous position. As is also the case withthe arrangement depicted in FIG. 14, the wearers ear is not covered byincorporated speaker enclosure so that the wearer may readily hearambient sound or wear hearing protection in areas of high ambient noise.The inventors have discovered, somewhat surprisingly, that a speakerenclosure and/or bone conduction microphone according to the inventionworks well when mounted as shown in FIG. 14.

The embodiments of the invention described herein are provided forpurposes of explaining the principles thereof, and are not to beconsidered as limiting or restricting the invention since manymodifications may be made by the exercise of skill in the art withoutdeparting from the scope of the invention as defined in the appendedclaims.

1. A communication apparatus comprising: a vibration conductionmicrophone including a housing, a transducer that is positioned in thehousing and art acoustic isolator that is also positioned in the housingand disposed about the transducer; said acoustic isolator including aholder holding a visco-elastic material, said transducer comprising anaccelerometer, said housing comprising a flexible body configured toreceive the accelerometer, the acoustic isolator and holder; a speakerenclosure including a speaker and arranged to couple vibrations from thespeaker to bone of a wearer; and attachment means coupled to each ofsaid microphone and said speaker enclosure to facilitate attachment toan item of headgear for placement of said microphone and speakerenclosure against a rearward portion of the wearer's head in use.
 2. Ahelmet mountable communication apparatus, including transducing meansconsisting of a vibration conduction microphone and a speaker enclosure;whereto, the transducing means is mounted at the rear of the helmet sothat in use the transducing means contacts the rear of a wearer's head;and wherein the vibration conduction microphone comprises a housing andan acoustic isolator that is also positioned in the housing, theacoustic isolator being disposed about the transducing means, saidacoustic isolator including a visco-elastic material; said acousticisolator further including a holder holding the visco-elastic material,said transducing means comprising an accelerometer, said housingcomprising a flexible body configured to receive the accelerometer,acoustic isolator and holder.
 3. The helmet mountable communicationsapparatus of claim 2, wherein the speaker enclosure comprises a housingfor a speaker, the housing defining at least one opening: a resilientdiaphragm that is attached to the housing and that is configured to makecontact with the head of a person, in use; and a membrane that isarranged on the housing to seal the at least one opening so that thespeaker is shielded from water.
 4. A speaker enclosure as claimed inclaim 3, in which the housing defines first and second openings.
 5. Aspeaker enclosure as claimed in claim 4, in which the resilientdiaphragm is arranged on the housing to seal the first opening and themembrane is arranged on the housing to seal the second opening.
 6. Aspeaker enclosure as claimed in claim 4 or claim 5, in which anacoustically transparent cover is positioned on the housing to protectthe second opening.
 7. A speaker enclosure as claimed in any one ofclaims 3 to 6, in which a speaker is mounted in the housing and anelectrical cable is connected to the speaker to transmit electricalsignals to the speaker, the housing defining an aperture foraccommodating the electrical cable and a sealant being interposedbetween the cable and the housing, the sealant being selected to providestrain relief to the electrical cable.
 8. A speaker enclosure as claimedin claim 7, in which a mounting means is arranged on the housing, themounting means being configured to receive a strap, belt or the like. 9.A speaker enclosure as claimed in claim 7 or claim 8, in which atransducer is arranged in the housing adjacent the resilient diaphragmso that the speaker enclosure can be used to pick up vibrations from awearer as well as to transfer vibrations to the wearer.
 10. A helmetmountable communications apparatus according to claim 2 wherein thetransducing means is mounted to an internal support of the helmet.
 11. Acommunication apparatus according to claim 1, wherein the speakerenclosure includes: a first region to couple vibrations from the speakerto bones of the wearer's head; and a second region to couple vibrationsfrom said speaker element to air for conventional hearing by the wearer.12. A communication apparatus according to claim 11, wherein saidspeaker enclosure includes: a housing about a speaker; and a resilientdiaphragm attached to the housing, said diaphragm comprising the firstregion to couple vibrations from the speaker to bones of the wearer'shead; the housing defining at least one opening comprising the secondregion to couple vibrations from said speaker to air for conventionalhearing by the wearer.
 13. A communication apparatus according to claim12, including a membrane arranged on the housing to seal the at leastone opening thereby shielding the speaker from water.
 14. Acommunication apparatus according to claim 13, including an acousticallytransparent cover for the first opening.
 15. A communication apparatusaccording to claim 12, including an electrical cable connected to thespeaker to transmit electrical signals to the speaker, the housingdefining an aperture accommodating the electrical cable and a sealantinterposed between the cable and the housing, the sealant being selectedto provide strain relief to the electrical cable.
 16. A communicationapparatus according to claim 12, in which a transducer is arranged inthe housing adjacent the resilient diaphragm so that the speakerenclosure can be used to pick up vibrations from the wearer as well asto transfer vibrations to the wearer.
 17. A communication apparatusaccording to claim 1, wherein the attachment means comprises: a firstheadgear strap engagement means fast with the vibration conductionmicrophone to receive a strap of the headgear; and a second headgearstrap engagement means fast with the vibration conduction speakerenclosure to receive said, or an additional, strap of the headgear. 18.A communication apparatus according to claim 17, wherein the first andsecond headgear strap engagement means include recesses formed intorespective bodies of the vibration conduction microphone and thevibration conduction speaker enclosure to receive the headgear straps.19. A communication apparatus according to claim 1, wherein theattachment means comprises a support structure to which the vibrationconduction microphone and the vibration conduction speaker enclosure aremounted.
 20. A communication apparatus according to claim 19, whereinthe headgear comprises a helmet and wherein the attachment means isadapted to be mounted to an internal support of the helmet.
 21. Acommunication apparatus according to claim 19, wherein the headgearcomprises a helmet and wherein the attachment means is adapted to beconnected to a nape adjustment strap of the helmet.
 22. A vibrationconduction microphone that includes: a housing; a transducer that ispositioned in the housing; and an acoustic isolator that is alsopositioned in the housing, the acoustic isolator being disposed aboutthe transducer, said acoustic isolator including a vico-elasticmaterial, said acoustic isolator further including a holder holding thevisco-elastic material, said transducer comprising an accelerometer,said housing comprising a flexible body configured to receive theaccelerometer, acoustic isolator and holder.